The proposed indication for GSK1940029 is topical treatment of acne, the early clinical plan will evaluate the irritation potential of GSK1940029 (Study SCD117225 - 3 Part study); and safety, tolerability and pharmacokinetics of GSK1940029 (Study SCD117226 - 2 Part study), after topical administration on healthy subjects and acne patients. Study SCD117226 will be a randomized, single-blind, dose-rising study to evaluate the safety, tolerability and preliminary pharmacokinetics of single and 14 day repeat topical applications of GSK1940029 gel on the intact skin of healthy human subjects. Part 1: (single-dose) subjects will receive 0.3% or 1% GSK1940029 (or matching vehicle), as a single approximately (App) 24 hour (h) (22.5h) application to a surface area of 400 square centimeter (cm^2) (0.3%), 400 cm^2 (1%) or 1200 cm^2 (1%), respectively, in each of three sequential cohorts. Part 2: (repeat-dose) subjects will receive 0.3% or 1% GSK1940029 (or matching vehicle), as 14 daily App24h (22.5h) application to a surface area of 400 cm^2 (0.3%), 400 cm^2 (1%) or 1200 cm^2 (1%), respectively, in each of three sequential cohorts. Parts within Study SCD117225 and Study SCD117226 will have interdependencies. No significant primary irritation signal in Study SCD117225 Part 1 (primary irritation) would allow initiation of Study SCD117226 Part 1. Once safety, tolerability and exposure information are determined in Study SCD117226 Part 1, then Part 2 (cumulative irritation) of Study SCD117225 may be initiated along with Part 2 of Study SCD117226. No significant cumulative irritation signal (study SCD117225 Part 2) in combination with adequate 14-day safety (study SCD117226 Part 2) would allow initiation of Part 3 (facial irritation) of Study SCD117225.